Process for the production of methyl ketones

ABSTRACT

A non-catalytic vapor phase process for the production of methyl ketones having the following structural formula:   WHEREIN R1, R2, R3 and R4 are hydrogen, a straight or branched chain alkyl radical having 1 to 8 carbon atoms wherein the total number of carbon atoms in all of said alkyl radicals is no greater than 12 carbon atoms, a phenyl radical, or a phenyl radical wherein 1 to 3 hydrogen atoms are substituted by a straight or branched chain alkyl radical having 1 to 3 carbon atoms, and wherein there are no more than 2 phenyl radicals, comprising admixing acetone with an olefin having the following structural formula:

United States Patent 1 Aprahamian, deceased June 17, 1975 PROCESS FOR THE PRODUCTION OF METHYL KETONES [75] Inventor: Nazar S. Aprahamian, deceased, late of West Nyack, N.Y., Aida Aprahamian, executrix [22] Filed: June 13, 1972 [21] Appl. No.: 262,308

OTHER PUBLICATIONS Faraday Encyclopedia, Hydrocarbon Compounds, C to C Vol. lb, p. 66, (1956). Richter, Textbook of Organic Chemistry, p. 29, (1938).

Primary Examiner-D. Horwitz Attorney, Agent, or FirmS. R. Bresch [57] ABSTRACT A non-catalytic vapor phase process for the production of methyl ketones having the following structural formula:

wherein R, R R and R are hydrogen, a straight or branched chain alkyl radical having 1 to 8 carbon atoms wherein the total number of carbon atoms in all of said alkyl radicals is no greater than 12 carbon atoms, a phenyl radical, or a phenyl radical wherein l to 3 hydrogen atoms are substituted by a straight or branched chain alkyl radical having 1 to 3 carbon atoms, and wherein there are no more than 2 phenyl radicals, comprising admixing acetone with an olefin having the following structural formula:

R R C=CR R wherein R, R R and R are as defined above at a temperature in the range of about 300 to about 650C. wherein the molar ratio of acetone to olefin is in the range of about 0.1 to about 10 mols of acetone per mol of olefin.

13 Claims, No Drawings PROCESS FOR THE PRODUCTION OF METHYL KETONES FIELD OF THE INVENTION This invention relates to a process for the production of methyl ketones and, more particularly, to the production of such ketones by effecting a reaction between an olefin and acetone.

DESCRIPTION OF THE PRIOR ART Methyl isobutyl ketone (MIBK) is a well known industrial solvent for the most commonly used coating resins such as nitrocellulose, acrylates, vinyls, and alkyds. Branched ketones exemplified by MIBK have recently come under fire as pollutants since they are considered to be photochemically active and thus detrimental to the environment. Local air pollution regulations such as Rule 66 in Los Angeles County, Calif. and Regulation V in Philadelphis, Pa. have severely circumscribed the use of such branched ketones.

As a substitute for MIBK, methyl-n-butyl ketone (MNBK) has been proposed and accepted, not only because it is considered to be a non-pollutant, but because of its superiority in applications similar to MIBK.

A need has arisen, therefore, for a simple and economical process for the production of MNBK and the like using easily available lose cost reactants.

SUMMARY OF THE INVENTION An object of this invention, then, is to provide a simple, economical route to methyl ketones by using inexpensive common reactants.

Other objects and advantages will become apparent hereinafter.

According to the present invention, a noncatalytic vapor phase process has been discovered for the production of methyl ketones having the following structural formula:

wherein R, R R and R are hydrogen, a straight or branched chain alkyl radical having 1 to 8 carbon atoms wherein the total number of carbon atoms in all of said alkyl radicals is no greater than 12 carbon atoms, a phenyl radical, or a phenyl radical wherein l to 3 hydrogen atoms or substituted by a straight or branched chain alkyl radical having 1 to 3 carbon atoms, and wherein there are no more than 2 phenyl radicals,

comprising admixing acetone with an olefin having the following structural formula:

wherein R. R R and R are as defined above at a temperature in the range of about 300 to about 65C. wherein the molar ratio of acetone to olefin is in the range of about 0.1 to about mols of acetone per mol of olefin.

The reaction can be characterized as a high temperature condensation or coupling reaction of an olefin with acetone. The process in which the reaction takes place appears advantageous because it can be performed in one step using low cost materials.

DESCRIPTION OF THE PREFERRED EMBODIMENT The process can be carried out by feeding a mixture of acetone and olefin into a reaction vessel. The inner surface of the reaction vessel which is in contact with the reaction mixture is preferably an inert material such as glass. Pyrex and Vycor heat and chemical resistant glassware are particularly suitable. A glasslined polytetrafluoroethylene coated stainless steel autoclave can be used advantageously along with metal surfaces such as stainless steel. Tubular, back-mixed, or loop reactors made of these materials can also be used together with multi-point injection to maintain a particular ratio of reactants.

The olefin used in the instant reaction can be defined by the following structural formula:

wherein R R R and R are as defined above. Examples of the olefin are ethylene, propylene, n-butene, npentene, n-hexene, n-heptene, n-octene, styrene, hexene-3, heptene-2, heptene-3, octene-2, octene-3, octene-4, isobutylene, isopentene, and various branched isomers of the formulas C H C H CH and C H for example. It should be pointed out that where branched olefins are used, a branched ketone will be the major product as a general rule.

The most useful commercially of the olefins in view of the products produced are ethylene, propylene, nbutene, and styrene.

In batch and semi-continuous processes, the acetone is generally introduced into the reaction vessel in liquid form. In continuous processes, however, prevaporization is preferable prior to introduction of the acetone into the reactor although the liquid form can be used if desired.

The olefin is generally introduced into the reactor in the same state that it is in at room temperature and at mospheric pressure; however, it can be introduced in gaseous or liquid form as desired. In continuous processes, again, it is preferable to pre-vaporize the liquid olefins prior to introduction into the reactor.

The amounts of acetone and olefin introduced initially into the reactor can be defined in molar ratios. The molar ratio of acetone to olefin can be in the range of about 0.1 to about 10 mols of acetone per mol of olefin and is preferably in the range of about 0.5 to about 2 mols of acetone per mole of olefin.

The temperature of the reactor is maintained in the range of about 300 to about 650C. and is, preferably, in the range of about 400 to about 550C. Temperatures are particularly important in this noncatalytic reaction, and the efficiencies of the desired product will be decreased significantly on a divergence of more than 25C. from the preferred range.

The pressure in the reactor is maintained in the range of about 50 psia (pounds per square inch absolute) to about 3,000 psia and is, preferably, in the range of about 300 to about 1,500 psia. Pressures as low as atmospheric pressure may be used although the reaction rate is slow and, consequently, the productivity (in terms of time) is so low that lowpressures are not ,commercially feasible. Higher pressures can also be used,

seasons a The tube is first evacuated to about 10 torr by use of a vacuum station. Nitrogen is introduced thereafter in certain of the examples. A preweighed quantity of acetone is then introduced into the reactor through one ofthe valves. The tube is cooled to liquid nitrogen temperature and re-cvacuated (where N is not used). Propylene gas is then introduced from a 4 liter reserout, again, these pressures are not commercially feasible or practical. The pressur in the examples are stated in terms of pounds per square inch gauge (psig) v-lhich is about one atmosphere greater than psia.

The interior of the reaction vessel should be essen- 5 tially oxygen-f 3c and, to this end, it can be evacuated or an atmosphere comprising nitrogen or other inert gaS C2111 06 us d. voir filled with propylene at atmospheric pressure. The

As mentioned previously, hatch, semi-continuous. or reactor is warmed to room temperature and placed in continuous operations can be used and there is no spean oven heated to about 600C. A. reaction temperacial order for the introduction of the reactants. ture in the range stated hereinafter is attained in eight This is u n nly i r ion and care should be minutes and the temperature is controlled in that range talten to use inert reactor surfaces rather than. for exby a temperature regulator. ample, stainless steel, ii optimum efficiencies are to be R i products l d b the use or a vapor attained 1 phase chromatograph (VPC), in some cases in corn Recovery, separation and analysis of products and junction irh a mass t o ter unreacted materials are accomplished by conventional Amoums 1' h reactants propylene d agetong i 113-3305 millimols; amounts of the products. M1951 and l t 18K,

Analysis of the products ot a typical hatch run oi suhin pemem by Weight f m product? f d; tempera l PromsS Wmmill 21001993 and 1 1 f ttirc range in C.; initial pressure in pounds per square acted is as iolltnvsz methyl n-huty! hCtOIlC, methyl iso inch gauge i reaction ti ng i i d i butyl ltetonc, and methyl cyclopentane as major pi'odsome CZ1SQS percent Conversion am set f h i ucts; isopropyl eyclohexane, npropyl cyelohexane, xy- 13,1 1 balow i' atmosphfle i d i E lenes, and rnesitylene in intermediate quantities; and i 21,, 6 7 3 d 9 P m Conversion i l lat d small quantities of '1'" cni.:-l, methyl ethyl hetone, as f ll methyl cyclohexene, 5-hexene-2one, toluene, and benzene are also found. in the presence of acid-washcd stainless steel wool, 21 major product is inesityl oxide and some 2-methy1-lpentene-4-one is found. Qlmewnc X 100 weight percent of unreacted acetone weight percent oi unreactcd The reactions are carried out in a 1. liter P res."

, acetone combustion tube, 18 inches in length with a 2 inch thweight percent w, z n .t V 1., V 1 5 acetone amctti. bnc end or the tube 1.. flanged .rno fitted with CUIWCTWL LC a glass to metal coupling With the other end. ot the tube percent conversion is closed in a manner irnilar to the closed end of a test tube. A. polytetratluoroetixylene gasket is used at the on is taken from a chromnlograni and area percent is approximately equal Reaction Percent Reaction Example Propylene Acetone 'lernperature Pressure Time lVlNBK MlBK Conversion Time 1 2K6 2 425 A 485 380 60 2.9 75 2 286 2 455 90 675 15 9.4. 1.7 3 280 2 480 75 15 13.3 3.0 25 -l 2146 5 550 10 8.4 (1.1 20 5 21th 2' 400 1 11.3 2.0 30 6 276 2 700 15 12.6 3t) 7 27 1 4 700 1 v 8.6 A 30 S .186 2 700 30 7.1 60 9 S72 2 700 15 4.7 30

Percent Reaction Percent Reaction Percent t t 119131; MlBh. tonversion Time MNBK MIBK Conversion Time IVINBK MIBK Conversion 5 .2 74 2. 45 3-H) 9.7 4.9 75 38.3 12.0 3 5 12.7 (a 2 2.7.0 9.9 9.11 w

8.4 15 20.4 7.1 w 18.0 6.0 4 11.3 28.4 8.4 29.2 8.9 i.7 v 45 3.5

glass-metal interface. tilt? coupling is titted with a stainless steel cross-shaped swedgelocl; fitting.

the tuhe valves and a thermocouple fitted onto the cross-shaped o I I cu cca cn xlcx a a wherein R, R R and R are as defined above at a temperature in the range of about 300 to about 675C. wherein the molar ratio of acetone to olefin is in the range of about 0.1 to about mols of acetone per mol of olefin. 2. The process defined in claim 1 wherein the molar ratio of acetone to olefin is in the range of about 0.5 to

about 2 mols per mol of olefin.

3. The process defined in claim 2 wherein the temperature is in the range of about 400 to about 550C.

4. The process defined in claim 1 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.

5. The process defined in claim 2 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.

6. The process defined in claim 3 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.

7. The process defined in claim 3 wherein the olefin is ethylene.

8. The process defined in claim 3 wherein the olefin is propylene.

9. The process defined in claim 3 wherein the olefin is n-butene.

10. The process defined in claim 3 wherein the olefin is styrene.

11. The process defined in claim 1 wherein the pressure is in the range of about 50 to about 3,000 psia.

12. The process defined in claim 3 wherein the pressure is in the range of about 300 to about 1,500 psia.

13. The process defined in claim 6 wherein the pressure is in the range of about 300 to about 1,500 psia. 

1. A MON-CATALYSTIC VAPOR PHASE PROCESS FOR THE PRODUCTION OF METHYLKETONES HAVING THE FOLLOWING STRUCTURAL FORMULA
 2. The process defined in claim 1 wherein the molar ratio of acetone to olefin is in the range of about 0.5 to about 2 mols per mol of olefin.
 3. The process defined in claim 2 wherein the temperature is in the range of about 400* to about 550*C.
 4. The process defined in claim 1 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.
 5. The process defined in claim 2 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.
 6. The process defined in claim 3 wherein the olefin is selected from the group consisting of ethylene, propylene, n-butene, and styrene.
 7. The process defined in claim 3 wherein the olefin is ethylene.
 8. The process defined in claim 3 wherein the olefin is propylene.
 9. The process defined in claim 3 wherein the olefin is n-butene.
 10. The process defined in claim 3 wherein the olefin is styrene.
 11. The process defined in claim 1 wherein the pressure is in the range of about 50 to about 3,000 psia.
 12. The process defined in claim 3 wherein the pressure is in the range of about 300 to about 1,500 psia.
 13. The process defined in claim 6 wherein the pressure is in the range of about 300 to about 1,500 PSIA. 